… or any signal generator for that matter in order to align the IF section, including the notorious crystal filter and phasing circuits, of Vintage Receivers like the Hammarlund HQ145 and HQ129X. It takes about a half hour once you get used to it, perhaps an hour or so the first time. I’ve aligned my Hammarlunds with this procedure and found the units to be very close to factory spec as measured with standard lab equipment.

In this article we will look at a few of the big deficiencies of the Hammarlund HQ145 general coverage shortwave receiver, and put in some fixes. CW/SSB reception with AGC and S-Meter, stability issues, bandspread, and sensitivity on the high band will be addressed.

Once modified, the HQ145 turns out to be a very nice ham and general coverage receiver all the way up through 10 M. It’s like my wife: attractive, capable, and a pleasure to be with. Or, it could be said Sweet, Sensitive, and Stable!

In this article we look at the reduction in feedline loss when we use a BMU to mitigate impedance extremes at the base feedpoint of a Vertical or Inverted-L antenna. Naturally, these antennas are worked against a proper counterpoise radial system for decent efficiency, especially on the low bands.

We look at the cases of a 42 ft antenna, and use an average of the measured and modeled feedpoint impedance to calculate feedline losses* for 50 ft of RG8x and for 100 ft LMR400.

The BMU referred to here is:

A 9:1 UNUN for the mid and high bandsA Loading Coil, switched in instead of the UNUN, for the low bands

Below are presented the results of actual measurements as well as EZNec modeling of both a 90 ft long End/Base-Fed Inverted-L 45 ft high and 45 ft across, as well as a 45 ft long Inverted-L 23 ft high and 22 ft across. Measurements of both were taken with a combination of a RigExpert AA-1400 and an HP8510 Vector Network Analyzer.

The 90 ft antenna is suspended by a pair of tall LobLollies, and is driven against a counterpoise system consisting of 14 surface ground radials and a low chain link fence.